1. Field of the Disclosure
The present disclosure relates to a thrombectomy catheter, but more specifically relates to a rheolytic thrombectomy catheter with a self-inflating proximal balloon having drug infusion capabilities and, for purposes of brevity, is alternately referred to herein as a rheolytic thrombectomy catheter. The terms used herein are not intended to be limited to any particular narrow interpretation unless clearly stated otherwise in this document.
2. Description of the Prior Art
Prior art and its comparison to the devices of the present disclosure are partially set forth herein. Flow cessation of prior art devices to minimize hemolysis and for other reasons has been accomplished via a balloon on a proximally placed guide catheter or by way of proprietary occlusion guidewire technology, such as, but not limited to, the use of balloons on guidewires. With respect to thrombectomy performance, prior art cross stream jet catheter designs have been described in prior patents by the present inventors or assignees. Such prior art cross stream jet catheter designs use cross stream jets flowing between outflow orifices and inflow orifices located on an exhaust tube to impinge, macerate and carry thrombus debris away from a thrombus site and through the exhaust tube. In the present disclosure, as opposed to prior art thrombectomy catheters which place outflow orifices in the exhaust tube, outflow orifices are positioned on the periphery of a self-inflated balloon to provide significantly more effective thrombus removal. For example, a peripheral cross stream jet thrombectomy catheter exhaust tube may have the diameter of 2 mm (6 Fr) and may be treating an 8 mm blood vessel. Cross stream jets flowing outwardly from the side outflow orifices are used to liberate debris such that the thrombus may be evacuated by the inflow orifices. Ideally, these side exhaust jets would typically travel outwardly at an average of 3 mm to impinge and scrub thrombus deposits on a vessel wall. If the peripheral cross stream jet thrombectomy catheter exhaust tube is off center, which is the norm, the outwardly directed side outflow cross stream jets could travel up to 6 mm to impinge and scrub thrombus on a vessel wall. The side outflow orifices are typically less than 0.66 mm in diameter and as a result the cross stream jet may travel almost 10 diameters to impinge the vessel wall. As a cross stream jet travels, the surrounding fluid slows the cross stream jet, hence, the ability to remove debris is diminished. Compare the prior scenario to the devices of the present disclosure in which the outflow orifices are located on the periphery of a self-inflating balloon. The self-inflating balloon size and catheter are selected by the physician to match the treated vessel size in order that the balloon will always inflate to attempt to be in direct contact with the thrombus. Hence, the cross stream jets will travel a very short distance (i.e., less than 10 diameters) substantially unimpeded by surrounding fluids to impinge the thrombus with maximum velocity. Secondly, inflation of the self-inflating balloon ensures centering of the device so that the vessel is treated equally in all circumferential directions. This design enables a more effective and greater removal of tougher and more organized thrombus. Furthermore, it enables a greater and more uniform delivery of drugs into this tougher mural thrombus.
Vessel safety is improved and enhanced by use of devices of the present disclosure. In previous cross flow design thrombectomy catheters, vessel damage is primarily inflicted when the vessel wall is sucked in by the negative pressures at the inflow orifices to the point that the internal high velocity jet streams can damage the vessel wall. In fact, merely moving the catheter while the inflow orifices have been sucked onto the vessel wall is a likely mechanism for vessel damage from cross stream catheters. Vessel damage increases with the size of the inflow orifices and with the proximity of the high velocity fluid jet stream origin to the inlet orifice. In the case of devices of the present disclosure, an inlet gap (inlet orifice) is positionally located away from the vessel wall by the centering action of the self-inflating balloon.